Various wind power generating system that utilizes the rotative force of a wind turbine and generate electric power have been proposed. For example, Patent Literature 1 discloses a lift force type wind turbine for wind-power generation in which three wing-type blades are arranged around and in parallel with a vertical rotating shaft.
However, the lift force type wind turbine described in the Unexamined Japanese Patent Application Kokai Publication No. 2006-46306 has an issue of low conversion efficiency for converting wind energy to rotational energy of a wind turbine.